{"id":"CVE-2026-102916","revision":"4f47afcc8c99427bbe2b8bfafb7c36e3","records":[{"revision":"4f47afcc8c99427bbe2b8bfafb7c36e3","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-102916","aliases":[],"title":"Reachable assertion in illumos bhyve REP string instruction emulation allows guest to panic host","description":"A reachable assertion in the illumos bhyve instruction emulator allows a guest to panic the host. When emulating a REP-prefixed MOVS or STOS instruction that accesses guest MMIO, vie_emulate_movs() and vie_emulate_stos() in usr/src/uts/intel/io/vmm/vmm_instruction_emul.c do not clear the VIES_REPEAT status flag on the final iteration. For MMIO regions emulated in the kernel (the local APIC, I/O APIC and HPET), the stale flag causes a VERIFY assertion in vie_advance_pc() to fail, and the host panics. A privileged user within a guest VM can issue a REP MOVS or REP STOS instruction against the local APIC page to cause a denial of service of the host and every other guest running on it. The flaw has existed since 2020 (illumos-gate commit e0c0d44e), and affects any illumos distribution prior to illumos-gate commit 696ecf8d.","state":0,"publishedAt":"2026-10-09T14:12:08.832+00:00","modifiedAt":"2026-10-09T21:07:26.509+00:00","affected":[{"ecosystem":"https://illumos.org","name":"system/bhyve","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"illumos\",\n                    \"product\": \"illumos-gate\",\n                    \"platforms\": [\n                        \"x86\"\n                    ],\n                    \"collectionURL\": \"https://illumos.org\",\n                    \"packageName\": \"system/bhyve\",\n                    \"repo\": \"https://github.com/illumos/illumos-gate\",\n                    \"modules\": [\n                        \"kernel\",\n                        \"bhyve\",\n                        \"vmm\"\n                    ],\n                    \"programFiles\": [\n                        \"usr/src/uts/intel/io/vmm/vmm_instruction_emul.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"e0c0d44e917080841514d0dd031a696c74e8c435\",\n                            \"lessThan\": \"696ecf8debceed9dc33937d8c8e111e4aeebfdae\",\n                            \"changes\": [\n                                {\n                                    \"at\": \"696ecf8debceed9dc33937d8c8e111e4aeebfdae\",\n                                    \"status\": \"unaffected\"\n                                }\n                            ],\n                            \"versionType\": \"git\"\n                        }\n                    ],\n                    \"defaultStatus\": \"affected\"\n                }"},{"ecosystem":"Vendor product","name":"OmniOS","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"OmniOS\",\n                    \"product\": \"OmniOS\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"any\",\n                            \"lessThan\": \"r151054\",\n                            \"versionType\": \"custom\"\n                        },\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"r151058\",\n                            \"lessThan\": \"r151058w\",\n                            \"changes\": [\n                                {\n                                    \"at\": \"r151058w\",\n                                    \"status\": \"unaffected\"\n                                }\n                            ],\n                            \"versionType\": \"custom\"\n                        },\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"r151056\",\n                            \"lessThan\": \"r151056aw\",\n                            \"changes\": [\n                                {\n                                    \"at\": \"r151056aw\",\n                                    \"status\": \"unaffected\"\n                                }\n                            ],\n                            \"versionType\": \"custom\"\n                        },\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"r151054\",\n                            \"lessThan\": \"r151054bw\",\n                            \"changes\": [\n                                {\n                                    \"at\": \"r151054bw\",\n                                    \"status\": \"unaffected\"\n                                }\n                            ],\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"defaultStatus\": \"affected\"\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:P/AU:Y/R:A/V:C","score":6.8,"severity":"MEDIUM"}],"references":["https://illumos.topicbox.com/groups/developer/T697a32b688807e56/cve-2026-102916-18491-bhyve-rep-prefix-instr-emulation-fumbles-flags","https://illumos.org/issues/18491","https://github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-102916","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-102916","identifiers":["CVE-2026-102916"]},"retained":false,"historicalAffected":[]}],"coverage":[]}